Comparison of thermal comfort performance of two different types of road vehicle climate control systems

The performance of climate control systems in vehicles becomes more and more important, especially against the background of the important relationship between compartment climate and driver mental condition and, thus, traffic safety. The performance of two different types of climate control systems, an un-air-conditioned heating/cooling device (VW) and an air-conditioning climate control unit (BMW), is compared using modern and practical evaluation techniques quantifying both the dynamic 3-D temperature distribution and the local air refreshment rate. Both systems suffer from considerable temperature gradients: temperature gradients in the U-AC (VW) car up to 8–9°C are encountered, while the AC (BMW) delivers clear improvement resulting in temperature gradients of 5–6°C. The experiments clearly demonstrate the effect of the presence of even a single passenger on the thermal regime, increasing the existing thermal discrepancies in the compartment with 15% independent of ventilation rate. Furthermore, in terms of air refreshment rates in the vehicle compartment, an air-conditioning unit halves the air refreshment time at all positions in the vehicle cabin, delivering a significant improvement in terms of human comfort. Similarly, extra air inlets in the back compartment of a car deliver progress in terms of cabin refreshment rate (93 s down to 50 s).     

Radiant heat and thermal comfort in vehicles

Infrared-reflective (IRR) treatment of automotive glass has been shown to reduce air temperature in vehicle cabins, thereby increasing fuel economy and occupant comfort. Its effect on radiant heat, however, may augment these benefits. In this study, the hypothesis that radiant heat affects subjective comfort ratings in a vehicle was tested. IRR films were systematically applied to the driver-side window of an outdoor stationary vehicle. In Phase 1, cabin air temperature was controlled while participants rated their thermal comfort. In Phase 2, air temperature was adjusted according to participants' responses. Results in Phase 1 showed that the IRR treatment improved thermal comfort on the left forearm, which was exposed to direct solar irradiance, but not whole-body thermal comfort. In Phase 2, participants indicated that they were comfortable at a higher air temperature (mean of 2.5 degrees F [1.4 degrees C]) with the IRR treatment than in the untreated condition. The results indicate that reducing radiant heat via IRR treatment affects subjective assessments of thermal comfort and allows occupants to maintain the same level of comfort in a warmer vehicle cabin. Applications of this research include future implementations of IRR treatment on automotive glass that may lead to greater fuel economy savings and occupant comfort than have previously been estimated.     

基于模糊控制的轿车空调温度控制系统研究

轿车空调是一个复杂的热力系统,由鼓风机、循环风门、混合风门、蒸发器和加热器等部分构成,其热负荷主要包括太阳辐射、车室内外温差、乘客热负荷和车速等.由热力学原理建立轿车空调系统的非线性模型,提出一种基于模糊推理的控制方法来实现轿车空调系统的温度控制,并利用型号为N15的轿车空调系统的参数进行Matlab仿真.仿真结果表明...     

基于PID的轿车空调系统设计

轿车空调系统由鼓风机、循环风门、混合风门、蒸发器、加热器、太阳辐射、室外空气对室内空气影响、乘客热负荷、车速等部分构成,由热平衡原理及能量守恒定律建立完整的轿车空调系统数学模型。针对空调模型,设计相应的PID控制器,来调节混合风门的开度以实现轿车车室温度调节。在Matlab 2009仿真软件中,利用Simulink工具箱建立空调控制系统的仿真模型。在仿真试验中,车室温度的调节过程大约需要1 min,温度控制准确度高。由于将一些热负荷考虑到模型中,能够较好地实现对干扰信号如太阳辐射强度、系统参数如蒸发器温度等变化量进行抑制。仿真试验表明所建立的数学模型和控制器设计是正确、可行的。     

汽车下护板对发动机舱散热性能的影响

为提高汽车发动机舱的散热性能,通过计算流体力学数值仿真研究汽车下护板对整车散热性能的影响。研究表明：在高速工况下,增加下护板后格栅和冷却模块进气量增加;在高负荷工况下,下护板可改善发动机舱的空气温度分布形态。下护板开口可增加冷却模块进气量,不开口时舱内温度较低,所以在整车设计时应综合考虑散热量和热害。下护板能明显减少风阻,但开口会减弱其效果,因此设计时应多方面考虑。     

基于MC9S08GB60的汽车电控悬架控制系统设计

对空气悬架的控制是提高车辆行驶平顺性的有效方法。以MC9S08GB60为控制芯片,以YBL6891H型客车的1/4车辆模型为研究对象,设计了一种客车用空气悬架的电子控制单元。该控制单元通过调整空气弹簧的刚度,降低车身垂直加速度,并采用模糊PID控制算法,提高控制精度。试验表明:该电子控制单元能有效降低车身垂直加速度,在改善车辆行驶平顺性的同时,提高了操纵稳定性。     

The influence of heated or cooled seats on the acceptable ambient temperature range

In 11 climate chamber experiments at air temperatures ranging from 15 to 45 degrees C, a total of 24 subjects, dressed in appropriate clothing for entering a vehicle at these temperatures, were each exposed to four different seat temperatures, ranging from cool to warm. In one simulated summer series, subjects were preconditioned to be too hot, while in other series they were preconditioned to be thermally neutral. They reported their thermal sensations, overall thermal acceptability and comfort on visual analogue scales at regular intervals. Instantaneous heat flow to the seat was measured continuously. At each ambient room temperature, the percentage dissatisfied was found to be a second-order polynomial function of local heat flow. Zero heat flow was preferred at an air temperature of 22 degrees C and the heat flow that minimized the percentage dissatisfied was found to be a single linear function of air temperature in all conditions. The analysis indicates that providing optimal seat temperature would extend the conventional 80% acceptable range of air temperature for drivers and passengers in vehicle cabins by 9.3 degrees C downwards and by 6.4 degrees C upwards.     

基于动态负荷需求分析的冷冻站测控系统设计

依据某病房办公楼空调系统的历史运行数据,进行了动态负荷需求分析,研究了空调运行冷负荷次数、时间频数和空调系统循环水温差随空调负荷变化趋势,提出了将模块化冷水机组4∶2∶4分组控制和空调水系统恒温差变频控制相结合的按需供冷方案。搭建了以PLC为核心的节能控制系统,经过运行实验,节能率26.1%,达到了很好的节能效果和经济性。     

基于Freescale单片机的电子控制空气悬架模糊PID控制

以 Freescale 公司的 MC9S08GB60A 单片机为控制芯片,以 YBL6891H 型客车的1/4车辆模型为研究对象,设计了一种客车用空气悬架的电子控制单元。该控制单元以车身垂直加速度的均方根为主要控制目标,采用了模糊 PID 控制算法,并用 MATLAB/SIMULINK 对该模型进行了仿真,仿真结果表明,利用该控制系统能很好地抑制客车的振动。     

A型地铁空调系统及客室内流场数值分析

为给目前国内A型地铁车辆的舒适度设计提供理论参考,针对地铁车辆静压风道结构特点,基于k-ε两方程湍流模型和SIMPLE算法,建立包含空调送风风道和客室的三维计算模型.对计算模型的空气流动和传热状况进行CFD数值计算.计算过程综合考虑车体壁面传热和人体散热等多种传热.分析计算结果得到客室内温度场和速度场的分布规律,并对空调通风设计方案进行量化评估.计算结果表明:客室内人体头部区域温度场分布均匀,平均温度为26.6℃,最大温差为6℃;车厢内有较理想的气流组织形式,速度分布范围为0.50~0.79 m/s,而且客室端部和中部区域人体头部周围速度较大.将计算结果与欧洲EN 14750-1标准进行对比分析,认为乘客的舒适性较好.     

Digital parameter-adaptive control of an air-conditioning plant

Two parameter-adaptive (self-tuning) control algorithms for multivariable systems are described. The algorithms are designed on the basis of linear input-output system models by the combination of recursive parameter estimation and control algorithms: a parameter-adaptive deadbeat controller and a parameter-adaptive optimal state controller. These controllers are applied to a two-input two-output air-conditioning pilot plant, which consists of an air heater and an air humidifier and whose output variables are the temperature and the relative humidity of the air measured at the air outlet. The air-conditioning plant is a nonlinear system and its linearized static and dynamic behaviour is strongly dependent on the operating point characterized mainly by the output variables and by the air flow rate through the plant. The results of the real-time control experiments indicate that it is possible to use the self-tuning features of the parameter-adaptive controllers to stabilize the controlled system after a short adaption phase and to achieve at least a satisfactory control performance for time varying air flow rates and for time varying setpoints of the output variables.     

智能控制在地铁通风空调系统中的应用

通风空调系统作为地铁中的重要设备系统之一,担负着对地下空间的空气温度、湿度、空气流速和空气品质进行控制的任务,而其能耗约为地下线能耗的30%以上,仅次于车辆牵引用电能耗,节能潜力相对较大。介绍了通风空调系统的运行模式和能耗测量方法,在分析能耗数据及能耗的基础上,提出了空调系统智能控制模块在环境综合监控系统(BAS)中的实现方案。     

Aspects to improve cabin comfort of wheel loaders and excavators according to operators

Comfort plays an increasingly important role in interior design of earth moving equipment. Although research has been conducted on vehicle interiors of wheel loaders and excavators, hardly any information is known about the operator's opinion. In this study a questionnaire was completed by machine operators to get their opinion about aspects which need to be improved in order to design a more comfortable vehicle interior. The results show that almost half of the operators rate the comfort of their cabin "average" or "poor". According to the operators, cab comfort of wheel loaders can be increased by improving seat comfort. Besides improving seat comfort, cabin comfort of excavators can be improved by changing the cab design (including dimensions, ingress/egress), view, reliability, and climate control.     

空调车室气流流场和温度场的数值模拟

空调车室气流流场和温度场研究是空调车室内气流组织设计及车室内舒适环境评价与研究的基础。空调车室的空气流场数值计算是一复杂热边界条件、气固耦合的传热数值计算问题。该文介绍了空调车室内空气流动的数学模型及复杂边界条件的处理，阐述了车室气流流场和温度场数值模拟采用整体求解法所应注意的问题，SIMPLE和SIMPLER算法的比较，以及通用微分方程中各项的处理方式。最后通过ANSYS／FLOYRAN软件对二维的车室内气流流场和温度场进行模拟，论证了此有限元软件在空调车室数值模拟上的可行性。     

分布式新能源汽车空调控制系统

空调的性能直接影响电动客车的动力性、舒适性及续航里程.设计了一种区域分布式多个小容量压缩机联和调节车厢温度的空调系统,通过摄像头对车厢不同区域进行综合管理,提出了不同区域不同乘客数目单独控制压缩机的方法.分析了基于人脸识别的乘员数量统计方法,建立了空调压缩机脉宽调制(PWM)控制模型,运用模糊神经网络算法进行控制.对装有空调系统的客车进行了高温试验,结果表明:空调运行良好,能够满足人体的热舒适性评价指标,达到了预期效果.     

纯电动汽车太阳能辅助空调控制系统的硬件设计

纯电动汽车车载动力电池是其唯一的动力源且很有限,辅助设备消耗的电能减少了纯电动汽车的续驶里程,尤其是空调,所以开发高效的纯电动汽车空调系统是纯电动汽车能够被市场接受的关键。将纯电动汽车顶盖布满太阳电池,可以使空调系统的制冷能力增强,同时还能增加纯电动汽车的行驶距离。对小型纯电动汽车的太阳能辅助空调系统进行研究,设计出适合该空调的自动控制系统,可为纯电动汽车创造出一个更加舒适的驾驶和乘座环境。     

一种飞行器燃料温控系统设计与优化

高空长航时飞行器由于长时间处于低温使用环境中,飞行器的燃料及其供给系统需进行温度控制功能设计,以保障飞行器长时间正常运行,以免造成飞行器损坏;飞行器燃料所处的低温环境受到内外部多种热源影响,且与飞行器的飞行任务剖面密切相关,温度环境复杂且难以有效计算仿真;针对飞行器在复杂低温环境中对燃料进行温度控制功能的需求,以及飞行器对温控系统高可靠性要求、资源条件限制苛刻等限制条件,开展了温控系统设计和优化,并完成了硬件设计和系统仿真;由于地面试验和真实环境差异较大,单一地面试验很难模拟真实热环境,对系统优化设计造成困难,针对性开展热环境分析,系统方案设计、地面试验和飞行试验联合验证,优化系统方案,实现了一种高效可靠,且易于工程应用的燃料贮箱温控功能,取得了良好的工程应用效果,同时该优化设计方法具有一定的扩展性。     

通信基站舒适性空调优化控制算法研究及应用

以一般通信基站舒适性定频空调的最佳温度设置为研究对象,结合空调控制终端和控制系统,利用数据库获取实时数据,建立数学模型,并运用MatLab编写算法,编译嵌入控制系统,将计算结果反馈调节远程空调控制终端,实现优化控制,降低通信基站空调电耗。     

通信基站舒适性空调优化控制算法研究及应用

以一般通信基站舒适性定频空调的最佳温度设置为研究对象．结合空调控制终端和控制系统,利用数据库获取实时数据,建立数学模型,并运用MatLab编写算法,编译嵌入控制系统,将计算结果反馈调节远程空调控制终端,实现优化控制,降低通信基站空调电耗。     

The influence of heated or cooled seats on the acceptable ambient temperature range

In 11 climate chamber experiments at air temperatures ranging from 15 to 45°C, a total of 24 subjects, dressed in appropriate clothing for entering a vehicle at these temperatures, were each exposed to four different seat temperatures, ranging from cool to warm. In one simulated summer series, subjects were preconditioned to be too hot, while in other series they were preconditioned to be thermally neutral. They reported their thermal sensations, overall thermal acceptability and comfort on visual analogue scales at regular intervals. Instantaneous heat flow to the seat was measured continuously. At each ambient room temperature, the percentage dissatisfied was found to be a second-order polynomial function of local heat flow. Zero heat flow was preferred at an air temperature of 22°C and the heat flow that minimized the percentage dissatisfied was found to be a single linear function of air temperature in all conditions. The analysis indicates that providing optimal seat temperature would extend the conventional 80% acceptable range of air temperature for drivers and passengers in vehicle cabins by 9.3°C downwards and by 6.4°C upwards.